Clownfish pair aggression question/help

[Pau Hana Reefer]

I was forced to split up my two clownfish last week for the well-being of the smaller of the two. The larger of the two had become overly aggressive towards the other in the days leading up to it. As soon as the white lights went off and only the blues were on, the larger would continuously chase the smaller. The smaller would hide against the wave pumps, flat on the sand against the glass, in the rockwork, etc. The day I removed the smaller one, his colors were completely faded, all fins were visibily damaged, he was very thin, and was exhausted and not moving much. He barely moved when I scooped him out of the DT and moved him into a 10 gallon QT. He has already improved significantly over the last 3 days.

I've had these two since January 2019 when they came as a pair. They got along fine for the past 1.5 years. The smaller of the two slowly caught up in size to the larger. This is when some of the problems started. I think the smaller of the two started to check if he could be the dominant one. The larger of the two didn't seem too bothered by it and just minded her own business for the next couple of months... and she then also went through a growth spurt. Once she was noticeably larger again, she would occasionally go after the smaller one. I attributed it to her re-enforcing her dominance and/or possibly mating behaviors. This increased over time and wasn't a concern until this past week.

Once the smaller one is nursed back to health, can I add him back the DT or will I likely need to keep them split up? Or one of those things where I won't know until I try?

 

[rwreef]

What type of clownfish? It is hard to say if they will be okay long term. I had a pair for about 3 or 4 yrs before the larger one got super aggressive and killed the male. These were typical percula clowns. The large female is now happy with a new man in a new tank. What are the other tank inhabitants?

 

[Mattiejay6]

Can you post pictures of both clowns please? If it’s maroons then this sounds pretty common.

however if perc/osc then maybe the male thought the female was sick, or not really a pair, and was trying to become the female sparking the challenge and ultimately losing. You can put the female in a timeout box inside the DT and once male is better see if they try to attack each other through the box. This sometimes works for an re intro if one is male and the other is female and pairing issues.

 

[Pau Hana Reefer]

Apologies for the late response... these past two weeks have been crazy with house projects and work. Thank you both for your response. Getting back to your questions...

What type of clownfish? It is hard to say if they will be okay long term. I had a pair for about 3 or 4 yrs before the larger one got super aggressive and killed the male. These were typical percula clowns. The large female is now happy with a new man in a new tank. What are the other tank inhabitants?

ORA Fancy Ocellaris Clownfish. Tankmates include Helfrichi Firefish, Red Head Solon Fairy Wrasse, Yellow Coris Wrasse, and CUC (shrimps, snails, hermit crabs). The clownfish were the first ones in the tank.

Can you post pictures of both clowns please? If it’s maroons then this sounds pretty common.

however if perc/osc then maybe the male thought the female was sick, or not really a pair, and was trying to become the female sparking the challenge and ultimately losing. You can put the female in a timeout box inside the DT and once male is better see if they try to attack each other through the box. This sometimes works for an re intro if one is male and the other is female and pairing issues.

Yeah, they're ocellaris. What's interesting were the growth spurts. The smaller one caught up and was about the same size as the larger one. But once that happened, the original larger one then took off with her own growth spurt. What concerned me was that the smaller one was submitting to the larger one. But the larger one was relentless with her attacks.

I looked for some pictures and realize that I haven't taken any good pictures pictures of the two since last year. Here is the original picture from LiveAquaria Diver's Den (January 2019):

Here they are in June 2019. The smaller one is on the left:

Here's the smaller one from the morning after I took him out of the DT the other week. He already looked a little better since I took him out the night before. The color change with the black belly happened during the growth spurt and hasn't changed much since around March. Sorry for the poor picture quality.

Here's another one of the smaller one from this morning. He's looking a lot better and doing great. Fins healed up nicely.

 

[chizerbunoi]

Mine would always fight when Actinics were on only as well. You can try reintroducing them. Just leave the whites on as well and see how they do. The good news is that in a weeks time they should heal back again.

 

[Pau Hana Reefer]

Mine would always fight when Actinics were on only as well. You can try reintroducing them. Just leave the whites on as well and see how they do. The good news is that in a weeks time they should heal back again.

How bad did they go at it? DId it just stop or did you have to take action?

Yeah, I was originally planning on reintroducing him back into the DT to see if there is any chance they'll get along. I was told by a LFS owner that they likely will need to be split up. So I think I'll likely have to use the suggestion mentioned earlier about using a separation box to see what happens. I might also do this when only my blues are on.

 

[chizerbunoi]

Every situation is different. My tank has lots of anemones for the clowns to hid into. So I didn’t have to separate them. But as soon as whites came on at 1%, they were fine again.

Maybe you don’t have spaces like that so the female can chase the male all around the tank?

I would start with putting the male into the isolation box for a few days. See how they react when the female sees him. She should be curious and he should dance the submission dance every time. Then let him out.

another easy way is to move him into egg crate leaving against the wall corner. It will allow him to go through but not her. Then he can escape to safety each time. But I think your female is too small still and this might not work as she can. Squeeze through it too.

 

[Pau Hana Reefer]

So my wife has felt really bad about the lone fish in the 10 gallon tank gave me permission this past week to set up second tank to house the clownfish and some new tankmates!

So question now is... do I really want to even try putting him back in the main DT or do I use this ticket to set up a second tank? ;Woot

 

[chizerbunoi]

I would try them together again. They were a pair before. If it doesn’t work out then...your decision. It’s more work to have two to maintain versus one which you put all your effort into. But if your looking to breed you might rather have some other varieties? Then again that would make 3 as you also have a quarantine tank.

For me personally I would upgrade my current tank and make it the way I want. Reefing is expensive, and the cost to buy nice equipment/livestock is more important than multiple tanks. Then most important is time on maintenance. This is after downsizing from multiple tanks in the 25 years I’ve been in the fish keeping hobby. My former clownfish pair was 9 years old so I was quite attached to them.

That doesn’t mean that I wouldn’t setup multiple tanks again in the future. If your ready then do it.

 

[ThRoewer]

I have actually seen a number of reports on this issue and it seems to be related to the light and what the fish see under different light conditions.

Normally, anemonefish recognize each other by the shape of the white of their head bands. Hans Fricke showed this in experiments in the Red Sea at Eilat, Israel in the 1970s. Once the head band is altered the fish is no longer recognized by its partner and attacked.

It could very well be that under actinic light the head band shape changes appearance for the clownfish and the female no longer recognizes her mate and attacks him. This is most probable if you switch T5s or LEDs on/off instead of slowly dimming them up or down.